MBSS Site Summary for: PG-N-097-121-97


Located on HORSEPEN BR in the Patuxent River upper watershed, 8-digit code: 02131104.
This stream was visited in the spring on 3/5/1997 and again in the summer on 6/24/1997.

Index of Biotic Integrity (IBI) Results:

An Index of Biotic Integrity (IBI) is a scientific tool used to identify and classify stream health. An IBI associates anthropogenic influences on a stream or with biological condition in the stream, and is formulated using data developed from biosurveys.
Details on the development and application of MBSS IBIs are in this document.
Fish IBI Fair - 3.7 / 5.0
Benthic IBI Fair - 3.6 / 5.0

Land Use

Land use can provide important information for determining stream health.
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Catchment area 3,533 acres A highly channelized urban stream with concrete banks. An example of a highly channelized urban stream.
Urban Land Use 27.4 %
Agricultural Land Use 23.3 %
Forested Land Use 40.2 %


Stream showing woody debris, logs, and rocky substrate.
An example of woody debris in a stream.

Physical Stream Habitat
Instream Habitat 8/20 (Marginal)
Epifaunal Substrate 4/20 (Poor)
Velocity/Depth Diversity 14/20 (Suboptimal)
Pool Quality
Pool Extent = meters 		14/20 (Suboptimal)
Riffle Quality 11/20 (Suboptimal)
Shading 80 %
Embeddedness 85 %
The embeddedness, a measure of silt on the stream bottom, was 85%. This is relatively high, and may exclude some biota.


Stream Water Quality:
Water temperature 18.3 ° C
Dissolved oxygen (DO) 9 mg/L
pH (lab) 6.88
Conductivity 198 µmho/cm
Alkalinity
(acid neutralizing capacity) 		495.8 µeq/L
Dissolved organic carbon (DOC) 6.9 mg/L

Biological Stream Condition:

Surveys of the organisms living within a stream can give indications of stream health. Species richness, or the number of different species present, as well as indicator species (species whose presence, absence or abundance can serve as a measure of environmental conditions) are informative for stream health. 		Close-up of a mayfly indicator species.

Fish Survey Results:
The following 9 fish species were collected.
Sensitive taxa: Green, Tolerant: Red, Intermediate: Gold.
Common name Count
Rosyside Dace 66
Blacknose Dace 54
Fallfish 17
Least Brook Lamprey 9
American Eel 7
Tessellated Darter 7
White Sucker 6
Eastern Mudminnow 1
Pumpkinseed 1
Biologists sampling fish communities.
Electrofishing to sample fish communities.

Amphibians and Reptiles:
Northern Green Frog
Northern Two-Lined Salamander

Crayfish:
Orconectes limosus

Exotic Plants:
No exotic plants noted.
 

Benthic Macroinvertebrates:
Sensitive taxa: Green, Tolerant: Red, Intermediate: Gold.
Genus/Family Common Name Count
Prostoma Freshwater Nemertean (Ribbon Worm) 10
Tubificidae Aquatic Worm 9
Eukiefferiella Non-Biting Midges 7
Parametriocnemus Non-Biting Midges 7
Stegopterna Black Fly 5
Hydrobaenus Midge 4
Paratanytarsus Non-Biting Midges 4
Thienemannimyia Non-Biting Midges 3
Hemerodromia Tiny Fly 3
Cheumatopsyche Net-Spinning Caddisfly 3
Lumbriculidae Worm 2
Pseudorthocladius Non-Biting Midges 2
Enchytraeidae Aquatic Worm 2
Orthocladiinae A Non-Biting Midges 2
Natarsia Non-Biting Midges 1
Sympotthastia Non-Biting Midges 1
Zavrelimyia Non-Biting Midges 1
Limnephilidae Northern Casemaker Caddisfly 1
Ancyronyx Spider Riffle Beetle 1
Boyeria Spotted Darner Dragonfly 1
Ephemerella Sulphur Mayfly 1
Hydropsyche Net-Spinning Caddisfly 1
Argia Narrow-Winged Damselfly 1
Pisidium Freshwater Pea (Pill) Clam 1
Nigronia Megaloptera (Dark Fishfly) 1
Cricotopus/Orthocladius Midge 1
Gomphidae Clubtail Dragonfly 1
Gomphus Clubtail Dragonfly 1
Tipula Crane Fly 1
Calopteryx Damselfly 1
Simulium Black Fly 1
Crangonyx Amphipod 1
Stygobromus Amphipod 1
Kick net sampling for macroinvertebrates.
Sampling with a kick net.

Information disclaimer: The information and data on this page is for guidance and general planning purposes only. It should not be used to make decisions on specific matters.